The present invention relates to an apparatus for controlling operation of an industrial robot.
Industrial robots capable of articulation with PTP (point-to-point) control, for example, have an arm, movable up and down, with a chuck or other tool atttached to a distal end of the arm for gripping and moving a desired object. According to ordinary control processes, the arm is first moved in a horizontal plane to a preset position, and after the arm has been completely stopped, an actuator, such for example, as an air cylinder for vertical drive, is operated to move the chuck and hence the object upward and downward.
Immediately before the arm reaches the preset position, however, the drive voltage in an arm driving servo system is lowered to provide cushioning against shocks and maintain positioning accuracy. This results in a reduction in speed of travel of the arm. The starting of the actuator is delayed since it is operated after the arrival of the arm at the preset position has been confirmed. Therefore, industrial robots have suffered from a long machine cycle.
The actuator is actually put into effective operation generally with a slight time lag after a start signal has been entered. There are many sequence programs for practical industral robots, which would not have execution problems if the actuator were operated simultaneously with operation of other parts.